edu.snu.dolphin.bsp.examples.ml.sub.MapOfIntVSumCodec.java Source code

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Here is the source code for edu.snu.dolphin.bsp.examples.ml.sub.MapOfIntVSumCodec.java

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/*
 * Copyright (C) 2015 Seoul National University
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *         http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package edu.snu.dolphin.bsp.examples.ml.sub;

import edu.snu.dolphin.bsp.examples.ml.data.VectorSum;
import org.apache.mahout.math.DenseVector;
import org.apache.mahout.math.Vector;
import org.apache.reef.io.serialization.Codec;

import javax.inject.Inject;
import java.io.*;
import java.util.HashMap;
import java.util.Map;

/**
 * Codec for encoding and decoding a map of Integer vs. Vector Sum
 */
public final class MapOfIntVSumCodec implements Codec<Map<Integer, VectorSum>> {

    @Inject
    public MapOfIntVSumCodec() {
    }

    @Override
    public byte[] encode(final Map<Integer, VectorSum> map) {

        /* This codec does not assume consistent centroid vector sizes(dimensions).
         * Therefore to specify the initial data size,
         * a quick iteration over the input list to compute
         * the sums of vector sizes is required.
         */
        int vectorSizeSum = 0;
        for (final VectorSum vectorSum : map.values()) {
            vectorSizeSum += vectorSum.getSum().size();
        }

        final ByteArrayOutputStream baos = new ByteArrayOutputStream(
                Integer.SIZE + Integer.SIZE * 3 * map.size() + Double.SIZE * vectorSizeSum);
        try (final DataOutputStream daos = new DataOutputStream(baos)) {
            daos.writeInt(map.size());
            for (final Integer integer : map.keySet()) {
                final VectorSum vectorSum = map.get(integer);
                daos.writeInt(integer);
                daos.writeInt(vectorSum.getSum().size());
                for (int j = 0; j < vectorSum.getSum().size(); j++) {
                    daos.writeDouble(vectorSum.getSum().get(j));
                }
                daos.writeInt(vectorSum.getCount());
            }
        } catch (final IOException e) {
            throw new RuntimeException(e.getCause());
        }

        return baos.toByteArray();
    }

    @Override
    public Map<Integer, VectorSum> decode(final byte[] data) {
        final ByteArrayInputStream bais = new ByteArrayInputStream(data);
        final Map<Integer, VectorSum> resultMap = new HashMap<>();

        try (final DataInputStream dais = new DataInputStream(bais)) {
            final int mapSize = dais.readInt();
            for (int i = 0; i < mapSize; i++) {
                final int mapInt = dais.readInt();
                final int vectorSize = dais.readInt();
                final Vector vector = new DenseVector(vectorSize);
                for (int j = 0; j < vectorSize; j++) {
                    vector.set(j, dais.readDouble());
                }
                final int count = dais.readInt();
                resultMap.put(mapInt, new VectorSum(vector, count));
            }
        } catch (final IOException e) {
            throw new RuntimeException(e.getCause());
        }

        return resultMap;
    }
}